Abstract Introuction: The slender Loris is a unique tiny arboreal, nocturnal primate. Steady declining of the species they are enlisted under endangered species. Many the histological studies are available pertaining to Hypophysis Cerebri of slender Loris, but histomorphometry have been poorly studied. Hence this study is carry out the histo-mophometic analysis and the anatomical aspects of Hypophysis Cerebri in slender Loris. Materials and Methods: The ten perfused brain of slender loris were embedded incelloidin and serial sections were prepared in sagittal planes at 50 micron thickness. They were stained incresyl fast violet and observed to study the histology. The surface area of pars distalis, pars intermedia, pars tuberalis, pars nervosa were calculated using histo-morphometric technique. Results and discussion: The average weights of pars distalis, pars intermedia pars tubularis and pars nervosa in slender Loris are 71 per cent, 2 per cent, 8 per cent, and 19 per cent respectively. Interestingly this data could be concomitant with data of cat those are in similar nocturnal behavior. Nocturnal behavior of this animal may have affected melanocyte production that might have resulted in pars intermedia be 3 % of the gland. As evidenced by histo-morphoetry and weight the manifestation of pars tubertalis could be depends upon photoperiodicity and animal behavior. Conclusion, In conclusion, the nature of pars intermedia and pars tuberalis could be depends upon photoperiodicity and adaptive behavior of the animal. This work recapitulates the research on neruo-anatomical aspects in this rare and forgotten species. Moreover this preliminary work might provide the opportunity to comprehend the comparative anatomy